Altitude sickness

Altitude sickness is the harmful effect of high altitude. The mildest form is known as acute mountain sickness (AMS)
Causes
It is caused by rapid exposure to low amounts of oxygen at high elevation.
Altitude
The severity of the disorder is related to the speed of ascent and the altitude reached. These symptoms disappear when going to lower altitudes. It occurs from 2,500 meters in altitude, up to the so-called "death zone" at 7,500 meters in altitude.
Hypoxia
The main cause is hypoxia (lack of oxygen in the body). Atmospheric pressure decreases with height, which affects the bio-availability of oxygen, since the pulmonary alveoli are not capable of transporting the same amount of oxygen to the blood as in a situation of higher pressure. Although it is known that hypoxia is the cause of this problem, the exact mechanism by which it causes it is still unknown.

The amount of oxygen available to sustain mental and psychological attention decreases as altitude increases. The availability of oxygen and nitrogen, as well as their density, decrease with increasing altitude.
Dehydration
Dehydration due to accelerated loss of water vapor due to altitude can lead to symptoms of altitude sickness. The speed with which one ascends, the initial height, physical activity, as well as individual susceptibility are factors that contribute to this discomfort.
Prevention
Altitude sickness can be prevented by climbing slowly. In most cases, symptoms are temporary and usually reduce as altitude acclimatization occurs. However, in extreme cases, altitude sickness can be fatal.

 References 

 Other websites 


 Merck Manual entry on altitude sickness
 Altitude Illness Clinical Guide for Physicians 

Category:Diseases
Category:Injuries
Category:Medical emergencies
Category:Mountain climbing
Category:Skiing
Category:Symptoms